Michigan senior Lion Kim came into Augusta National last Monday as an unknown college student who somehow had qualified for the Masters by winning the U.S. Amateur Public Links in July.

Most figured it was a fluke.

Whispers of “Who is that guy?” and “What is he doing here?” could be heard on the sidelines of the revered fairways and outside the flawless greens during the practice rounds Monday and Tuesday.

By Friday, the whispers had changed. For those who had seen Kim play throughout the week, they no longer had questions. They had statements.

“That kid is gonna be good,” “He has some real talent,” and “I wonder when he’s gonna turn pro,” replaced the questions from earlier in the week.

Kim will be back to Augusta. But it won’t be long drives or flashy shots that will get him there. It won’t be a Phil Mickelson-esque trick shot between two trees — it’ll be what lies just inches away from the ‘M’ emblazoned on his polo all week long.

It’ll be Kim’s heart.

“Lion works harder than anybody I’ve coached,” Michigan coach Andrew Sapp said the week before Kim left for the Masters.

It seemed cliché at the time — a line any sports reporter has heard hundreds of times about many different players. Every coach says that about his or her captain.

But then I spent a week covering Kim, seeing his work ethic first-hand for five days.

During the practice rounds Monday and Tuesday, Kim studied every angle on each green, every shot from each fairway, every drive from each tee box.

He spent hours on the range and the putting green with caddie Louis Laurence and instructor Brian Mogg, working on every possible shot he might encounter on the No. 1 golf course in the world.

He picked the brains of PGA Tour Champions Zach Johnson and K.J. Choi, asking for any advice they might be able to give him — anything that could help him weave his way through the hallowed grounds of Augusta National.

And within the first three days, it was clear that Kim had the work ethic to become a professional golfer — though I still wasn’t convinced he was good enough to be one.

That thought began to change as soon as I saw him stripe the first drive of his Masters career down the middle and birdie the hole, as thousands of fans looked on in awe.

By the time Friday’s round came to a close, there was no doubt that it wouldn’t be Kim’s last time in Augusta.

Of the five birdies Kim tallied in his two rounds, three of them came after a bogey — and one came on the first hole Thursday.

He never looked rattled, always fighting back when he had a bad hole.

While playing-mates Davis Love III and Jose Maria Olazabal fell further and further down the leader board — Olazabal finished plus-6 and Love, plus-8 — Kim played on, competing as though he would be playing through the weekend.

While Love III continually missed putts inside ten feet, mumbling to himself in frustration and staring up to the sky in disbelief, Kim continually drilled the putts to stay in contention, never allowing the falters of his playing mates or the pressure of the situation get the best of him.

He didn’t have the booming drives of Love III or the perfect swing of Olazabal — but Kim had the heart and the will that neither of the other two had during the week. There was a reason he finished first of the three.

And when it was all but over on Friday — when the cut line hovered around plus-1 and Kim ended the two days at plus-4 — I talked to Kim’s caddy, Louis Laurence.

“I’ll bet he goes back to the range now anyway,” Laurence said with a smile.

And with the roar of a Tiger in the background, the heart of a Lion went back to work.